Nato is standing firm behind the United States in its determination to crush international terrorism, the organisation's secretary general Lord Robertson insisted today.

Lord Robertson said that last week's Article 5 declaration by the Alliance's 19 members that an attack on one of its members was an attack on all had real meaning.

Dismissing suggestions that the coalition against terrorism which US President George Bush and Prime Minister Tony Blair are trying to put together was looking "wobbly", Lord Robertson responded: "That is not my impression. I don't think that's the case at all.

"I watched President Chirac yesterday on television in the US, there wasn't a flicker of doubt in his mind that they would stand by the US.

"Chancellor Schroeder made it absolutely clear yesterday that Germany accepts not just its obligations under Article 5, but its obligations to stand by a country that has been attacked in a way that Germany and other countries could be as well.

"So I can tell you that the Alliance stands firm and the declaration made last Wednesday was not only historic, it was actually practical in its implications too."

Lord Robertson warned: "We are up against people who are using techniques that would have been unimaginable only a few weeks ago, and I think therefore we have got to think differently.

"It is no use having the capabilities of the past when you are dealing with these dangerous threats of the future. And that is why a lot of things have to be rethought. So yes, we are in for a long campaign, but if we don't win it, then I think the consequences could be catastrophic," Lord Robertson told BBC Radio 4's Today programme.

@Text:Lord Robertson stressed that the Americans had yet to clarify exactly what support they wanted from the Alliance.

"They have not yet said clearly that this was an attack from abroad and have ruled out domestic terrorism. They haven't said it publicly and they haven't said it privately.

"That is a decision they will have to make when they have amassed all the evidence that they have got. They are then obliged to come and tell Nato ...

"They have said that the evidence is increasingly pointing towards (Osama) bin Laden and his terrorist organisation, but they have not made a formal declaration of that and they haven't made the formal declaration to Nato.

"And they will do that in due course. That is the first step.

"The second step is to come and request help from the Alliance and from the individual allies. And it will be up then to the individual countries to decide in what way they want to help the Americans with the particular mission they are involved in.

"Of course it doesn't preclude the US acting on its own or acting with a number of countries inside or outside of Nato as part of a coalition of the willing."